Marine seismology companies invest heavily in the development of marine seismic surveying equipment and seismic data processing techniques in order to obtain accurate, high-resolution seismic images of subterranean formations located beneath a body of water. High-resolution seismic images of a subterranean formation are used to determine the structure of subterranean formations, discover petroleum reservoirs, and monitor petroleum reservoirs during production. A typical marine seismic survey is carried out with a survey vessel that tows one or two seismic sources and a number of streamers below the surface of the body of water. A seismic source is composed of an array of source elements, such as air guns. The streamers are elongated cable-like structures that are towed behind the survey vessel in the direction the survey vessel is traveling. Each streamer includes a number of receivers that generate seismic data in response to detecting pressure and/or particle motion wavefields. The streamers are arranged substantially parallel to one another to form a seismic data acquisition surface. The survey vessel contains seismic acquisition equipment, such as navigation control, seismic source control, seismic receiver control, and seismic data recording equipment.
A typical marine seismic survey is carried out by activating the seismic source above a subterranean formation, which produces an acoustic signal called a source wavefield of defined shape (or source signature) that expands outward in all directions. A portion of the source wavefield travels downward through the body of water and into the subterranean formation. At each interface between different types of rock and sediment, a portion of the source wavefield is refracted, a portion is transmitted, and another portion is reflected back from each interface into the body of water to propagate toward the free surface. The seismic data generated by the receivers ideally represents just the wavefields that are reflected back into the body of water from the subterranean formation and travel directly to the receivers. However, because the source wavefield expands outward in all directions, the receivers also detect other wavefields. For example, a portion of the source wavefield travels directly from the source to the receivers, and another portion of the source wavefield travels upward to the free surface and is reflected downward creating a second time-delayed downward traveling source wavefield that interacts with the subterranean formation to produce secondary reflected wavefields from the subterranean formation. As a result, the seismic data is contaminated with the source signature and source ghost effects.